An Exchange offline address book (OAB) is an Address Book that contains one or more address lists. It is availalble to Exchange Client software (e.g Outlook 2007) when users are not connected to Exchange Server and are offline.
OABs are not generated frequently in a day because OAB generation process consumes much system resources if they contain hundreds of email addresses. Instead they are normally generated once or twice in a day depending upon the size of the OAB and need of the organization owning that OAB.
Sometimes its necessary to immediately generate the OAB when a new email address is added to Exchange System, so that the new email address is immediately available to outlook (or) other clients through downloading the latest OAB.
For immediate OAB generation and distribution (both PF, and web based distribution through CAS) I do following steps:
1. Run Update-OfflineAddressbook “offline address book” in Exchange Management Shell. e.g
Update-OfflineAddressbook “Default offline address book”
2. Restart System Attendant Service on the OAB Generation Server (Mailbox Server). This service is responsible for generating the OAB by communicating with Active Directory infrastructure.
3. Either run following command in EMS
or just restart File Distribution Service on CAS Server.
File distribution service copies the OAB from the Mailbox Server, where System Attendant Service puts OAB in a shared folder “C:\Program Files\Microsoft\Exchange Server\ExchangeOAB”. Outlook clients then download the OAB from CAS published OAB Virtual Directory.